The distribution, damage and parasite complex of a new alfalfa pest, Melanagromyza sojae (Zehnt) 1 in the Jamahiriya

Abstract

Melanagromyza sojae (Zehnt) has not so far been reported from the Jamahiriya. Its larvae were found to mine alfalfa stems at Tagoura in August 1977. Mature alfalfa in all the fields surveyed in 17 localities of the Western region was later found infested. The percentage of mined stems in different fields was 66.6-100, 66.6-100 and 10.0-26.6 during September, October and November, 1977, respectively. Similar observations were noted in 1978-79 in two fields at Tagoura and Sidi Mesri, infestations of

46.6-85.8% in August-October and only 23.7% in November 1978. Infestation dropped to 6.7% in December and was negligible in January 1979. The damage was slight, (6.7-20%) in February-April. It increased progressively in May-July reaching a peak in August-October. Two Pteromelids, Halticoptera circulurs (Walk) and Sphegigaster ni-grocornis (Nees) and a Tetracampid, Platynocheilus cupifrons (Nees) were reared from the pest pupae and larvae, respectively. Parasitised insects were found at Tagoura and in the other localities surveyed. The occurrence of these species also seems to be a new record for the Jamahiriya.

' Diptera, Agromyzidae